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1.
Mol Microbiol ; 120(3): 324-340, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37469248

RESUMEN

OLE RNA is a ~600-nucleotide noncoding RNA present in many Gram-positive bacteria that thrive mostly in extreme environments, including elevated temperature, salt, and pH conditions. The precise biochemical functions of this highly conserved RNA remain unknown, but it forms a ribonucleoprotein (RNP) complex that localizes to cell membranes. Genetic disruption of the RNA or its essential protein partners causes reduced cell growth under various stress conditions. These phenotypes include sensitivity to short-chain alcohols, cold intolerance, reduced growth on sub-optimal carbon sources, and intolerance of even modest concentrations of Mg2+ . Thus, many bacterial species appear to employ OLE RNA as a component of an intricate RNP apparatus to monitor fundamental cellular processes and make physiological and metabolic adaptations. Herein we hypothesize that the OLE RNP complex is functionally equivalent to the eukaryotic TOR complexes, which integrate signals from various diverse pathways to coordinate processes central to cell growth, replication, and survival.


Asunto(s)
Extremófilos , ARN , Extremófilos/metabolismo , Bacterias/genética , Bacterias/metabolismo , ARN no Traducido/genética , Ribonucleoproteínas/genética , Ribonucleoproteínas/metabolismo
2.
Proc Natl Acad Sci U S A ; 118(9)2021 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-33619097

RESUMEN

The OLE (ornate, large, and extremophilic) RNA class is one of the most complex and well-conserved bacterial noncoding RNAs known to exist. This RNA is known to be important for bacterial responses to stress caused by short-chain alcohols, cold, and elevated Mg2+ concentrations. These biological functions have been shown to require the formation of a ribonucleoprotein (RNP) complex including at least two protein partners: OLE-associated protein A (OapA) and OLE-associated protein B (OapB). OapB directly binds OLE RNA with high-affinity and specificity and is believed to assist in assembling the functional OLE RNP complex. To provide the atomic details of OapB-OLE RNA interaction and to potentially reveal previously uncharacterized protein-RNA interfaces, we determined the structure of OapB from Bacillus halodurans alone and in complex with an OLE RNA fragment at resolutions of 1.0 Å and 2.0 Å, respectively. The structure of OapB exhibits a K-shaped overall architecture wherein its conserved KOW motif and additional unique structural elements of OapB form a bipartite RNA-binding surface that docks to the P13 hairpin and P12.2 helix of OLE RNA. These high-resolution structures elucidate the molecular contacts used by OapB to form a stable RNP complex and explain the high conservation of sequences and structural features at the OapB-OLE RNA-binding interface. These findings provide insight into the role of OapB in the assembly and biological function of OLE RNP complex and can guide the exploration of additional possible OLE RNA-binding interactions present in OapB.


Asunto(s)
Bacillus/química , Proteínas Bacterianas/química , ARN Bacteriano/química , ARN no Traducido/química , Ribonucleoproteínas/química , Secuencia de Aminoácidos , Bacillus/genética , Bacillus/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Secuencia de Bases , Sitios de Unión , Clonación Molecular , Cristalografía por Rayos X , Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Regulación Bacteriana de la Expresión Génica , Vectores Genéticos/química , Vectores Genéticos/metabolismo , Simulación del Acoplamiento Molecular , Conformación de Ácido Nucleico , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , ARN Bacteriano/genética , ARN Bacteriano/metabolismo , ARN no Traducido/genética , ARN no Traducido/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Ribonucleoproteínas/genética , Ribonucleoproteínas/metabolismo
3.
J Biol Chem ; 298(12): 102674, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36336078

RESUMEN

Ornate, large, extremophilic (OLE) RNAs represent a class of noncoding RNAs prevalent in Gram-positive, extremophilic/anaerobic bacterial species. OLE RNAs (∼600 nt), whose precise biochemical functions remain mysterious, form an intricate secondary structure interspersed with regions of highly conserved nucleotides. In the alkali-halophilic bacterium Bacillus halodurans, OLE RNA is a component of a ribonucleoprotein (RNP) complex involving at least two proteins named OapA and OapB, but additional components may exist that could point to functional roles for the RNA. Disruption of the genes for either OLE RNA, OapA, or OapB result in the inability of cells to overcome cold, alcohol, or Mg2+ stresses. In the current study, we used in vivo crosslinking followed by OLE RNA isolation to identify the protein YbxF as a potential additional partner in the OLE RNP complex. Notably, a mutation in the gene for this same protein was also reported to be present in a strain wherein the complex is nonfunctional. The B. halodurans YbxF (herein renamed OapC) is homologous to a bacterial protein earlier demonstrated to bind kink turn (k-turn) RNA structural motifs. In vitro RNA-protein binding assays reveal that OLE RNA forms a previously unrecognized k-turn that serves as the natural binding site for YbxF/OapC. Moreover, B. halodurans cells carrying OLE RNAs with disruptive mutations in the k-turn exhibit phenotypes identical to cells lacking functional OLE RNP complexes. These findings reveal that the YbxF/OapC protein of B. halodurans is important for the formation of a functional OLE RNP complex.


Asunto(s)
Proteínas Bacterianas , ARN , Proteínas Bacterianas/metabolismo , Sitios de Unión , Motivos de Nucleótidos , ARN no Traducido/genética
4.
RNA Biol ; 19(1): 1059-1076, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-36093908

RESUMEN

Riboswitch architectures that involve the binding of a single ligand to a single RNA aptamer domain result in ordinary dose-response curves that require approximately a 100-fold change in ligand concentration to cover nearly the full dynamic range for gene regulation. However, by using multiple riboswitches or aptamer domains in tandem, these ligand-sensing structures can produce additional, complex gene control outcomes. In the current study, we have computationally searched for tandem riboswitch architectures in bacteria to provide a more complete understanding of the diverse biological and biochemical functions of gene control elements that are made exclusively of RNA. Numerous different arrangements of tandem homologous riboswitch architectures are exploited by bacteria to create more 'digital' gene control devices, which operate over a narrower ligand concentration range. Also, two heterologous riboswitch aptamers are sometimes employed to create two-input Boolean logic gates with various types of genetic outputs. These findings illustrate the sophisticated genetic decisions that can be made by using molecular sensors and switches based only on RNA.


Asunto(s)
Aptámeros de Nucleótidos , Riboswitch , Aptámeros de Nucleótidos/química , Ligandos , ARN , Riboswitch/genética
5.
J Biol Chem ; 295(28): 9326-9334, 2020 07 10.
Artículo en Inglés | MEDLINE | ID: mdl-32376692

RESUMEN

Noncoding RNAs (ncRNAs) longer than 200 nucleotides are rare in bacteria, likely because bacterial genomes are under strong evolutionary pressures to maintain a small genome size. Of the long ncRNAs unique to bacteria, the OLE (ornate, large, extremophilic) RNA class is among the largest and most structurally complex. OLE RNAs form a ribonucleoprotein (RNP) complex by partnering with at least two proteins, OapA and OapB, that directly bind OLE RNA. The biochemical functions of the OLE RNP complex remain unknown, but are required for proper adaptation to certain environmental stresses, such as cold temperatures, short chain alcohols, and high magnesium concentrations. In the current study, we used electrophoretic mobility shift assays to examine the binding of OLE RNA fragments by OapB and found that OapB recognizes a small subregion of OLE RNA, including stem P13, with a dissociation constant (KD ) of ∼700 pm Analyses with mutated RNA constructs, and the application of in vitro selection, revealed that strong binding of OLE RNA by OapB requires a stem containing a precisely located single-nucleotide bulge and a GNRA tetraloop. Although the vast majority of bacteria with the ole gene also have the oapB gene, there are many whose genomes contain oapB but lack ole, suggesting that OapB has other RNA partners in some species that might exhibit similar structural features.


Asunto(s)
Bacillus/química , Proteínas Bacterianas/química , ARN Bacteriano/química , ARN no Traducido/química , Proteínas de Unión al ARN/química , Bacillus/genética , Bacillus/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , ARN Bacteriano/genética , ARN Bacteriano/metabolismo , ARN no Traducido/genética , ARN no Traducido/metabolismo , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo
6.
Am J Hum Genet ; 102(4): 696-705, 2018 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-29606302

RESUMEN

AEBP1 encodes the aortic carboxypeptidase-like protein (ACLP) that associates with collagens in the extracellular matrix (ECM) and has several roles in development, tissue repair, and fibrosis. ACLP is expressed in bone, the vasculature, and dermal tissues and is involved in fibroblast proliferation and mesenchymal stem cell differentiation into collagen-producing cells. Aebp1-/- mice have abnormal, delayed wound repair correlating with defects in fibroblast proliferation. In this study, we describe four individuals from three unrelated families that presented with a unique constellation of clinical findings including joint laxity, redundant and hyperextensible skin, poor wound healing with abnormal scarring, osteoporosis, and other features reminiscent of Ehlers-Danlos syndrome (EDS). Analysis of skin biopsies revealed decreased dermal collagen with abnormal collagen fibrils that were ragged in appearance. Exome sequencing revealed compound heterozygous variants in AEBP1 (c.1470delC [p.Asn490_Met495delins(40)] and c.1743C>A [p.Cys581∗]) in the first individual, a homozygous variant (c.1320_1326del [p.Arg440Serfs∗3]) in the second individual, and a homozygous splice site variant (c.1630+1G>A) in two siblings from the third family. We show that ACLP enhances collagen polymerization and binds to several fibrillar collagens via its discoidin domain. These studies support the conclusion that bi-allelic pathogenic variants in AEBP1 are the cause of this autosomal-recessive EDS subtype.


Asunto(s)
Alelos , Carboxipeptidasas/genética , Colágeno/metabolismo , Tejido Conectivo/patología , Síndrome de Ehlers-Danlos/genética , Mutación/genética , Proteínas Represoras/genética , Adulto , Secuencia de Aminoácidos , Carboxipeptidasas/química , Niño , Preescolar , Femenino , Fibroblastos/metabolismo , Fibroblastos/patología , Humanos , Masculino , Dominios Proteicos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas Represoras/química , Piel/patología , Piel/ultraestructura , Adulto Joven
7.
Proc Natl Acad Sci U S A ; 115(27): E6319-E6328, 2018 07 03.
Artículo en Inglés | MEDLINE | ID: mdl-29915070

RESUMEN

OLE (ornate, large, extremophilic) RNAs comprise a class of structured noncoding RNAs (ncRNAs) found in many extremophilic bacteria species. OLE RNAs constitute one of the longest and most widespread bacterial ncRNA classes whose major biochemical function remains unknown. In the Gram-positive alkaliphile Bacillus halodurans, OLE RNA is abundant, and localizes to the cell membrane by association with the transmembrane OLE-associated protein called OapA (formerly OAP). These characteristics, along with the well-conserved sequence and structural features of OLE RNAs, suggest that the OLE ribonucleoprotein (RNP) complex performs important biological functions. B. halodurans strains lacking OLE RNA (∆ole) or OapA (∆oapA) are less tolerant of cold (20 °C) and short-chain alcohols (e.g., ethanol). Here, we describe the effects of a mutant OapA (called PM1) that more strongly inhibits growth under cold or ethanol stress compared with strains lacking the oapA gene, even when wild-type OapA is present. This dominant-negative effect of PM1 is reversed by mutations that render OLE RNA nonfunctional. This finding demonstrates that the deleterious PM1 phenotype requires an intact RNP complex, and suggests that the complex has one or more additional undiscovered components. A genetic screen uncovered PM1 phenotype suppressor mutations in the ybzG gene, which codes for a putative RNA-binding protein of unknown biological function. We observe that YbzG protein (also called OapB) selectively binds OLE RNA in vitro, whereas a mutant version of the protein is not observed to bind OLE RNA. Thus, YbzG/OapB is an important component of the functional OLE RNP complex in B. halodurans.


Asunto(s)
Bacillus , Proteínas Bacterianas , Farmacorresistencia Bacteriana , Etanol/farmacología , Proteínas de Unión al ARN , Bacillus/genética , Bacillus/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Farmacorresistencia Bacteriana/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo
8.
Mol Microbiol ; 112(5): 1552-1563, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31461569

RESUMEN

OLE RNAs represent an unusual class of bacterial noncoding RNAs common in Gram-positive anaerobes. The OLE RNA of the alkaliphile Bacillus halodurans is highly expressed and naturally interacts with at least two RNA-binding proteins called OapA and OapB. The phenotypes of the corresponding knockouts include growth inhibition when exposed to ethanol or other short-chain alcohols or when incubated at modestly reduced temperatures (e.g. 20°C). Intriguingly, the OapA 'PM1' mutant, which carries two amino acid changes to a highly conserved region, yields a dominant-negative phenotype that causes more severe growth defects under these same stress conditions. Herein, we report that the PM1 strain also exhibits extreme sensitivity to elevated Mg2+ concentrations, beginning as low as 2 mM. Suppressor mutants predominantly map to genes for aconitate hydratase and isocitrate dehydrogenase, which are expected to alter cellular citrate concentrations. Citrate reduces the severity of the Mg2+ toxicity phenotype, but neither the genomic mutations nor the addition of citrate to the medium overcomes ethanol toxicity or temperature sensitivity. These findings reveal that OLE RNA and its protein partners are involved in biochemical responses under several stress conditions, wherein the unusual sensitivity to Mg2+ can be independently suppressed by specific genomic mutations.


Asunto(s)
Antibacterianos/farmacología , Bacillus/crecimiento & desarrollo , Magnesio/farmacología , ARN no Traducido/metabolismo , Ribonucleoproteínas/metabolismo , Aconitato Hidratasa/genética , Bacillus/genética , Ácido Cítrico/metabolismo , Etanol/farmacología , Isocitrato Deshidrogenasa/genética , ARN no Traducido/genética , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Ribonucleoproteínas/genética
9.
Adv Skin Wound Care ; 33(2): 91-97, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31972581

RESUMEN

OBJECTIVE: To develop and implement a point-of-care digital solution to streamline the creation and maintenance of wound care product formularies and promote cost-effective wound management. METHODS: Researchers used Design Thinking methodology to develop the Formulary Module, a point-of-care digital solution within a clinical and reimbursement decision support web application for wound care and hyperbaric clinicians. The module was implemented in a US hospital-based outpatient wound clinic as follows: A baseline list of products was established, with brands automatically grouped by product category. Brands within each dressing category were compared, and redundancy eliminated. Study authors assessed the financial impact of formulary implementation in the wound clinic by comparing inventory expenditure before and after implementation. RESULTS: Implementation of the digital Formulary Module resulted in a 36% decrease in products (67 to 43 across 22 types), 38.73% decrease in the monthly average dollar spent on chargeable products, 29.56% decrease in the average dollar amount spent on chargeable products per patient visit, and increased staff efficiency. CONCLUSIONS: The Formulary Module has the potential to increase the adoption of cost-effective practices in wound care significantly.


Asunto(s)
Sistemas de Atención de Punto , Úlcera Cutánea/terapia , Heridas y Lesiones/terapia , Análisis Costo-Beneficio , Bases de Datos Factuales , Formularios Farmacéuticos como Asunto , Humanos
10.
J Gen Intern Med ; 34(4): 591-597, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30091121

RESUMEN

BACKGROUND: Despite widespread implementation of mammographic breast density (MBD) notification laws, the impact of these laws on knowledge of MBD and knowledge of breast cancer risk is limited by the lack of tools to promote informed decision-making in practice. OBJECTIVE: To develop and evaluate whether brief, personalized informational videos following a normal mammogram in addition to a legislatively required letter about MBD result can improve knowledge of MBD and breast cancer risk compared to standard care (i.e., legislatively required letter about MBD included with the mammogram result). DESIGN/PARTICIPANTS: Prospective randomized controlled trial of English-speaking women, age 40-74 years, without prior history of breast cancer, receiving a screening mammogram with a normal or benign finding (intervention group n = 235, control group n = 224). INTERVENTION: brief (3-5 min) video, personalized to a woman's MBD result and breast cancer risk. MAIN MEASURES: Primary outcomes were a woman's knowledge of her MBD and risk of breast cancer. Secondary outcomes included whether a woman reported that she discussed the results of her mammogram with her primary care provider (PCP). KEY RESULTS: Relative to women in the control arm, women in the intervention arm had greater improvement in their knowledge of both their personal MBD (intervention pre/post 39.2%/ 77.5%; control pre/post 36.2%/ 37.5%; odds ratio (OR) 5.34 for change for intervention vs. control, 95% confidence interval (CI) 3.87-7.36; p < 0.001) and risk of breast cancer (intervention pre/post: 66.8%/74.0%; control pre/post 67.9%/ 65.2%; OR 1.42, 95% confidence interval (CI) 1.09-1.84; p = 0.01). Women in the intervention group were more likely than those in the control group to report discussing the results of their mammogram with their PCP (p = 0.05). CONCLUSIONS: Brief, personalized videos following mammography can improve knowledge of MBD and personal risk of breast cancer compared to a legislatively mandated informational letter. Trial Registration Clinicaltrials.gov (NCT02986360).


Asunto(s)
Densidad de la Mama , Neoplasias de la Mama/diagnóstico , Conocimientos, Actitudes y Práctica en Salud , Adulto , Anciano , Detección Precoz del Cáncer , Femenino , Humanos , Mamografía/estadística & datos numéricos , Tamizaje Masivo/métodos , Persona de Mediana Edad , Medición de Riesgo , Encuestas y Cuestionarios , Grabación en Video
11.
Anal Chem ; 90(7): 4711-4718, 2018 04 03.
Artículo en Inglés | MEDLINE | ID: mdl-29498261

RESUMEN

There are many gas phase compounds present in the atmosphere that affect and influence the earth's climate. These compounds absorb and emit radiation, a process which is the fundamental cause of the greenhouse effect. The major greenhouse gases in the earth's atmosphere are carbon dioxide, methane, nitrous oxide, and ozone. Some halocarbons are also strong greenhouse gases and are linked to stratospheric ozone depletion. Hydrocarbons and monoterpenes are precursors and contributors to atmospheric photochemical processes, which lead to the formation of particulates and secondary photo-oxidants such as ozone, leading to photochemical smog. Reactive gases such as nitric oxide and sulfur dioxide are also compounds found in the atmosphere and generally lead to the formation of other oxides. These compounds can be oxidized in the air to acidic and corrosive gases and contribute to photochemical smog. Measurements of these compounds in the atmosphere have been ongoing for decades to track growth rates and assist in curbing emissions of these compounds into the atmosphere. To accurately establish mole fraction trends and assess the role of these gas phase compounds in atmospheric chemistry, it is essential to have good calibration standards. The National Institute of Standards and Technology has been developing standards of many of these compounds for over 40 years. This paper discusses the development of these standards.

12.
J Gen Intern Med ; 33(10): 1729-1737, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30076569

RESUMEN

BACKGROUND: Use of breast cancer screening is influenced by factors associated with patients, primary care providers, practices, and health systems. OBJECTIVE: We examined the relative effects of these nested levels on four breast cancer screening metrics. DESIGN: A web-based survey was completed at 15 primary care practices within two health systems representing 306 primary care providers (PCPs) serving 46,944 women with a primary care visit between 1/2011-9/2014. Analyses occurred between 1/2017 and 5/2017. MAIN MEASURES: Across four nested levels (patient, PCP, primary care practice, and health system), frequency distributions and adjusted rates of primary care practice characteristics and survey results for four breast screening metrics (percent screened overall, and percent screened age 40-49, 50-74, and 75+) were reported. We used hierarchical multi-level mixed and random effects analysis to assess the relative influences of PCP, primary care practice, and health system on the breast screening metrics. KEY RESULTS: Overall, the proportion of women undergoing breast cancer screening was 73.1% (73.4% for ages 40-49, 76.5% for 50-74, and 51.1% for 75+). Patient ethnicity and number of primary care visits were strongly associated with screening rates. After adjusting for woman-level factors, 24% of the overall variation among PCPs was attributable to the primary care practice level, 35% to the health system level, and 41% to the residual variation among PCPs within practice. No specific provider-level characteristics were found to be statistically significant determinants of screening rates. CONCLUSIONS: After accounting for woman-level characteristics, the remaining variation in breast cancer screening was largely due to provider and health system variation.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Detección Precoz del Cáncer/métodos , Atención Primaria de Salud/organización & administración , Adulto , Anciano , Anciano de 80 o más Años , Detección Precoz del Cáncer/estadística & datos numéricos , Femenino , Encuestas de Atención de la Salud , Humanos , Mamografía , Tamizaje Masivo/métodos , Tamizaje Masivo/organización & administración , Tamizaje Masivo/estadística & datos numéricos , Massachusetts , Persona de Mediana Edad , New Hampshire , Atención Primaria de Salud/estadística & datos numéricos , Práctica Profesional/estadística & datos numéricos
13.
RNA Biol ; 15(3): 377-390, 2018 03 04.
Artículo en Inglés | MEDLINE | ID: mdl-29135333

RESUMEN

Orphan riboswitch candidates are noncoding RNA motifs whose representatives are believed to function as genetic regulatory elements, but whose target ligands have yet to be identified. The study of certain orphans, particularly classes that have resisted experimental validation for many years, has led to the discovery of important biological pathways and processes once their ligands were identified. Previously, we highlighted details for four of the most common and intriguing orphan riboswitch candidates. This facilitated the validation of riboswitches for the signaling molecules c-di-AMP, ZTP, and ppGpp, the metal ion Mn2+, and the metabolites guanidine and PRPP. Such studies also yield useful linkages between the ligands sensed by the riboswitches and numerous biochemical pathways. In the current report, we describe the known characteristics of 30 distinct classes of orphan riboswitch candidates - some of which have remained unsolved for over a decade. We also discuss the prospects for uncovering novel biological insights via focused studies on these RNAs. Lastly, we make recommendations for experimental objectives along the path to finding ligands for these mysterious RNAs.


Asunto(s)
Bacterias/genética , ARN Mensajero/química , Riboswitch , Levaduras/genética , Secuencias de Aminoácidos , Aptámeros de Nucleótidos , Ligandos , Modelos Moleculares , Conformación de Ácido Nucleico , ARN Bacteriano/química , ARN de Hongos/química
14.
Anal Bioanal Chem ; 410(24): 6247-6255, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29980807

RESUMEN

The noble gases, namely neon, argon, krypton and xenon, have many uses including in incandescent and gas discharge lighting, in plasma televisions, shielding gas in welding, in lasers for surgery and semiconductors, and in magnetic resonance imaging (MRI) of the lungs. When incorporating these noble gases in industries, especially the medical field, it is important to know accurately the composition of the noble gas mixture. Therefore, there is a need for accurate gas standards that can be used to determine the noble gas amount-of-substance fraction in the appropriate mixture application. A recent comparison of mixtures containing four noble gases in a helium balance showed mixed results among National Metrology Institutes. Significant differences, 0.7 to 3.8% relative, were seen in the analytical amount-of-substance assignments versus the gravimetric value of the noble gases in the comparison mixture when using "binary standards", i.e. neon in helium, argon in helium and krypton in helium, as applied by the National Institute of Standards and Technology. Post-comparison studies showed that when all four noble gases were included in the standards, the agreement between analytical and gravimetric values was within 0.05% relative. Further research revealed that different carrier gases (hydrogen, helium and nitrogen) resulted in varying differences between the analytical and gravimetric values assignments. This paper will discuss the findings of these analytical comparisons. Graphical abstract ᅟ.

15.
Public Health Nurs ; 35(4): 353-359, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29566271

RESUMEN

OBJECTIVES: A community-academic team implemented a study involving collection of quantitative data using a computer-based audience response system (ARS) whereby community partners led data collection efforts. The team participated in a reflection exercise after the data collection to evaluate and identify best practices and lessons learned about the community partner-led process. DESIGN & SAMPLE: The methods involved a qualitative research consultant who facilitated the reflection exercise that consisted of two focus groups-one academic and one community research team members. The consultant then conducted content analysis. Nine members participated in the focus groups. RESULTS: The reflection identified the following themes: the positive aspects of the ARS; challenges to overcome; and recommendations for the future. CONCLUSION: The lessons learned here can help community-academic research partnerships identify the best circumstances in which to use ARS for data collection and practical steps to aid in its success.


Asunto(s)
Investigación Participativa Basada en la Comunidad/métodos , Recolección de Datos/métodos , Grupos Focales/métodos , Relaciones Comunidad-Institución , Procesamiento Automatizado de Datos/métodos , Ejercicio Físico , Humanos , Investigación Cualitativa
16.
RNA ; 21(11): 1845-51, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26385510

RESUMEN

Hatchet RNAs are members of a novel self-cleaving ribozyme class that was recently discovered by using a bioinformatics search strategy. The consensus sequence and secondary structure of this class includes 13 highly conserved and numerous other modestly conserved nucleotides interspersed among bulges linking four base-paired substructures. A representative hatchet ribozyme from a metagenomic source requires divalent ions such as Mg(2+) to promote RNA strand scission with a maximum rate constant of ∼4 min(-1). As with all other small self-cleaving ribozymes discovered to date, hatchet ribozymes employ a general mechanism for catalysis involving the nucleophilic attack of a ribose 2'-oxygen atom on an adjacent phosphorus center. Kinetic characteristics of the reaction demonstrate that members of this ribozyme class have an essential requirement for divalent metal ions and that they might have a complex active site that employs multiple catalytic strategies to accelerate RNA cleavage by internal phosphoester transfer.


Asunto(s)
ARN Catalítico/genética , ARN/genética , Secuencia de Bases , Catálisis , Dominio Catalítico/genética , Cationes Bivalentes/metabolismo , Biología Computacional/métodos , Secuencia de Consenso/genética , Cinética , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Nucleótidos/genética , Especificidad por Sustrato/genética
17.
RNA ; 21(11): 1852-8, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26385507

RESUMEN

Pistol RNAs are members of a distinct class of self-cleaving ribozymes that was recently discovered by using a bioinformatics search strategy. Several hundred pistol ribozymes share a consensus sequence including 10 highly conserved nucleotides and many other modestly conserved nucleotides associated with specific secondary structure features, including three base-paired stems and a pseudoknot. A representative pistol ribozyme from the bacterium Lysinibacillus sphaericus was found to promote RNA strand scission with a rate constant of ∼10 min(-1) under physiological Mg(2+) and pH conditions. The reaction proceeds via the nucleophilic attack of a 2'-oxygen atom on the adjacent phosphorus center, and thus adheres to the same general catalytic mechanism of internal phosphoester transfer as found with all other classes of natural self-cleaving ribozymes discovered to date. Analyses of the kinetic characteristics and the metal ion requirements of the cleavage reaction reveal that members of this ribozyme class likely use several catalytic strategies to promote the rapid cleavage of RNA.


Asunto(s)
ARN Catalítico/genética , ARN/genética , Bacterias/genética , Secuencia de Bases , Catálisis , Biología Computacional/métodos , Secuencia de Consenso/genética , Cinética , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Nucleótidos/genética
18.
J Gen Intern Med ; 32(4): 449-457, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28070772

RESUMEN

BACKGROUND: Revised breast cancer screening guidelines have fueled debate about the effectiveness and frequency of screening mammography, encouraging discussion between women and their providers. OBJECTIVE: To examine whether primary care providers' (PCPs') beliefs about the effectiveness and frequency of screening mammography are associated with utilization by their patients. DESIGN: Cross-sectional survey data from PCPs (2014) from three primary care networks affiliated with the Population-based Research Optimizing Screening through Personalized Regimens (PROSPR) consortium, linked with data about their patients' mammography use (2011-2014). PARTICIPANTS: PCPs (n = 209) and their female patients age 40-89 years without breast cancer (n = 30,233). MAIN MEASURES: Outcomes included whether (1) women received a screening mammogram during a 2-year period; and (2) screened women had >1 mammogram during that period, reflecting annual screening. Principal independent variables were PCP beliefs about the effectiveness of mammography and their recommendations for screening frequency. KEY RESULTS: Overall 65.2% of women received >1 screening mammogram. For women 40-48 years, mammography use was modestly lower for those cared for by PCPs who believed that screening was ineffective compared with those who believed it was somewhat or very effective (59.1%, 62.3%, and 64.7%; p = 0.019 after controlling for patient characteristics). Of women with PCPs who reported they did not recommend screening before age 50, 48.1% were nonetheless screened. For women age 49-74 years, the vast majority were cared for by providers who believed that screening was effective. Provider recommendations were not associated with screening frequency. For women ≥75 years, those cared for by providers who were uncertain about effectiveness had higher screening use (50.7%) than those cared for by providers who believed it was somewhat effective (42.8%). Patients of providers who did not recommend screening were less likely to be screened than were those whose providers recommended annual screening, yet 37.1% of patients whose providers recommended against screening still received screening. CONCLUSIONS: PCP beliefs about mammography effectiveness and screening recommendations are only modestly associated with use, suggesting other likely influences on patient participation in mammography.


Asunto(s)
Actitud del Personal de Salud , Neoplasias de la Mama/diagnóstico por imagen , Detección Precoz del Cáncer/estadística & datos numéricos , Mamografía/estadística & datos numéricos , Atención Primaria de Salud/organización & administración , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Estudios Transversales , Detección Precoz del Cáncer/métodos , Femenino , Humanos , Persona de Mediana Edad , Relaciones Médico-Paciente , Médicos de Atención Primaria/psicología , Práctica Profesional/estadística & datos numéricos , Estados Unidos
19.
Nat Chem Biol ; 11(8): 606-10, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26167874

RESUMEN

Enzymes made of RNA catalyze reactions that are essential for protein synthesis and RNA processing. However, such natural ribozymes are exceedingly rare, as evidenced by the fact that the discovery rate for new classes has dropped to one per decade from about one per year during the 1980s. Indeed, only 11 distinct ribozyme classes have been experimentally validated to date. Recently, we recognized that self-cleaving ribozymes frequently associate with certain types of genes from bacteria. Herein we exploited this association to identify divergent architectures for two previously known ribozyme classes and to discover additional noncoding RNA motifs that are self-cleaving RNA candidates. We identified three new self-cleaving classes, which we named twister sister, pistol and hatchet, from this collection, suggesting that even more ribozymes remain hidden in modern cells.


Asunto(s)
Archaea/genética , Bacterias/genética , Genómica/métodos , ARN Catalítico/química , Algoritmos , Archaea/enzimología , Bacterias/enzimología , Humanos , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Motivos de Nucleótidos , Biosíntesis de Proteínas , Proteolisis , ARN Catalítico/genética , ARN Catalítico/metabolismo
20.
J Digit Imaging ; 30(2): 228-233, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-27844217

RESUMEN

We previously identified breast imaging findings from radiology reports using an expert-based information extraction algorithm as part of the National Cancer Institute's Population-based Research Optimizing Screening through Personalized Regimens (PROSPR) initiative. We validate this algorithm and assess inaccuracies in a different institutional setting. Mammography, ultrasound (US), and breast magnetic resonance imaging (MRI) reports of patients at an academic health system between 4/2013 and 6/2013 were included for analysis. Accuracy of automatically extracting imaging findings using an algorithm developed at a different institution compared to manual gold standard review is reported. Extraction errors are further categorized based on manual review. Precision and recall for extracting BI-RADS categories remain between 0.9 and 1.0, except for MRI (0.7). F measures for extracting other findings are 0.9 for non-mass enhancement (in MRI) and 0.8-0.9 for cysts (in MRI and US). Extracting breast imaging findings resulted in lowest accuracy for findings of calcification (range 0.4-0.6 in mammography) and asymmetric density (0.5-0.7 in mammography). Majority of errors for extracting imaging findings were due to qualifier-based errors, descriptors which indicate absence of findings, missed by automated extraction (e.g., "benign" calcifications). Our information extraction algorithm provides an effective approach to extracting some breast imaging findings for populating a breast screening registry. However, errors in information extraction when utilizing methods in new settings demonstrate that further work is necessary to extract information content from unstructured multi-institutional radiology reports.


Asunto(s)
Algoritmos , Mama/diagnóstico por imagen , Neoplasias de la Mama , Femenino , Humanos , Almacenamiento y Recuperación de la Información , Imagen por Resonancia Magnética , Mamografía , Estándares de Referencia , Ultrasonografía Mamaria
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